No disagreement that chorded keyboards are the most efficient, but, like you said, they require a steep learning curve. Expecting casual users to put in hours of learning for their daily use keyboard is ridiculous.
A “casual user” with lots of existing computer experience who wants to save himself from RSI but not spend effort learning something new should probably get something like a Matias ErgoPro, and be done with it. Anything remotely similar to an Ergodox is not for him.
By contrast, a “power user” who plans to invest a bunch of effort in keyboards, such as learning a new physical layout, customizing her layers, etc., should spring for the 50–70 key board, and then put some thought into the setup. She’ll type circles around the other guy.
You still don't overcome the difficulty of users being able to successfully identify the keys.
Identifying the keys sucks on absolutely every keyboard for every non-trivial piece of software. No keyboard comes with every software application’s shortcuts printed on the legends, so there are a bunch of arbitrary abstract relations to learn one way or another.
There’s nothing logical about any of the use of F keys in existing software. Putting a shortcut on e.g. spade symbol key + Q isn’t inherently any more or less reasonable than putting it on Alt + F4.
On the other hand, every time you have to reach for a key, and especially every time you have to look down at the keyboard to figure out which key to press, you end up causing a massive human performance hit.
Can you not accept that extra keys benefit both novice and experienced users?
No, I can’t. Speaking from direct personal experience using keyboards and watching many other people use keyboards, F keys are basically terrible for all levels. There’s a reason Apple, Google, and Microsoft demoted the F keys to be the second layer on their Macbook, Chromebook, and Surface type cover keyboards, and put functions like adjusting screen brightness and media controls on those keys instead: the F keys suck for casual users, and only a tiny percentage of people ever use them for anything.
We train novice users on the F keys all the time, and it makes interaction with our line-of-business software easy.
That’s a problem with your line-of-business software, but doesn’t really have too much bearing on keyboard enthusiasts’ new designs. If someone had a keyboard without physical F keys where to send the same key event to the computer used a layer, it would not be especially easier or harder to train them. (Frankly, someone with a custom keyboard who carefully designed their own layout can probably just train themselves on your keyboard shortcuts, if you hand them a piece of paper with the shortcuts listed on it. I doubt such people make up any appreciable fraction of your customers.)
If you want keyboard shortcut design feedback, you could start a different thread, and I’m sure several geekhackers would be willing to offer advice.
How does adding additional keys make a huge efficiency hit, when instead of one key press, I'm now forced to make at least two?
Because every time you need to move your whole hand off the home row, you need to do 2 separate re-orientations, each of which causes a time delay and interrupts your train of thought. I recommend you actually try timing this in a real-world experiment. Time your current keystroke in context the middle of standard typing, then set up a key binding which can be easily reached without any hand movement or contortion, give yourself a few days or a week to learn it, and then time yourself again. I promise you’ll see an improvement.
Examples of keys which cause slowdowns all the time on a standard keyboard: delete, escape, arrows, the “navigation cluster”, various multi-modifier shortcuts, F keys.
If you redesign the keyboard to move these functions to be within reach (as an easy example, by moving the delete/backspace key to be one half of a split spacebar) it makes a dramatic improvement.
Similarly, putting some kind of pointing device directly adjacent to the home hand position makes a big improvement when switching between mousing and typing. IBM did internal experiments showing that each time a pointing stick is uses instead of a separate mouse, it saves seconds of time.
If you’re willing to put some time and effort in, I highly recommend building or buying a column-staggered keyboard with sufficient thumb keys such as an Ergodox, keyboard.io, Kinesis Advantage, or similar, and then re-locating numbers onto a layer (e.g. in a numpad-like arrangement) near the home row instead of using the usual number row. After some practice, you’ll see very noticeable improvements in fluency typing mixed text and numbers compared to using the top row or using a separate numpad. Likewise, if you’re a programmer, I strongly recommend moving common symbols (parenthesis, arithmetic operators, etc.) to layers and positioning them in easy reach. If you commonly use F keys, put those on a layer, perhaps under the same keys as the corresponding numbers to make it easy to remember which is which.
If you set things up carefully, you’ll end up with an overall much more fluent experience. You’ll improve your speed, reduce your error rate, reduce the number of interruptions to your train of thought, keep yourself more comfortable and stave off RSI, and so on. If you give yourself as an end user the ability to add more shortcuts whenever you need them (ideally via real-time macro recording, but it could even be in some offline config step), you’ll give yourself a platform on which you can keep improving constantly, instead of hitting the low skill ceiling of standard keyboards.
How does adding keys to the top or bottom of a keyboard make worse ergonomics for pointing devices?
That was with reference to the “piles of unnecessary keys” on a standard keyboard. That includes the arrow keys, the forwards delete/home/end/pgup/pgdn keys, and the number pad. F keys don’t have much impact on external pointing devices.
Your reasons for opposing extra keys are dogmatic.
I’m just telling you how to make the best general-purpose computer keyboard for a “power user” who is willing to invest time and effort, based on my own extensive experience and research; I’m not commenting at all on how to make the best selling product, how to build the best point of sale keyboard or flight simulator input device or stenography keyboard, or how to make life easy for someone who wants to stick to what they’re used to.
Anyhow, type with whatever kind of input device you want; no skin off my back.